const API_URL = '/api/v1/index.php?request=';

const state = {
    user: JSON.parse(localStorage.getItem('user')) || null,
    token: localStorage.getItem('token') || null,
};

const routes = {
    '/': homePage,
    '/login': loginPage,
    '/learners': learnersPage,
    '/assessments': assessmentsPage,
};

async function init() {
    window.addEventListener('hashchange', router);
    router();
    updateNav();
}

function router() {
    const hash = window.location.hash || '#/';
    const path = hash.substring(1);
    const page = routes[path] || routes['/'];
    page();
}

function updateNav() {
    const navLinks = document.getElementById('nav-links');
    if (!state.token) {
        navLinks.innerHTML = `
            <li class="nav-item"><a class="nav-link" href="#/login">Login</a></li>
        `;
        return;
    }

    navLinks.innerHTML = `
        <li class="nav-item"><a class="nav-link" href="#/">Dashboard</a></li>
        <li class="nav-item"><a class="nav-link" href="#/learners">Learners</a></li>
        <li class="nav-item"><a class="nav-link" href="#/assessments">Assessments</a></li>
        <li class="nav-item"><a class="nav-link" href="#" id="logout-btn">Logout</a></li>
    `;

    document.getElementById('logout-btn').addEventListener('click', (e) => {
        e.preventDefault();
        logout();
    });
}

function logout() {
    localStorage.removeItem('token');
    localStorage.removeItem('user');
    state.token = null;
    state.user = null;
    window.location.hash = '#/login';
    updateNav();
}

async function apiFetch(endpoint, options = {}) {
    const url = API_URL + endpoint;
    const defaultOptions = {
        headers: {
            'Content-Type': 'application/json',
            ...(state.token ? { 'Authorization': `Bearer ${state.token}` } : {})
        }
    };
    const response = await fetch(url, { ...defaultOptions, ...options });
    const data = await response.json();
    if (response.status === 401) {
        logout();
        throw new Error('Unauthorized');
    }
    return data;
}

function render(html) {
    document.getElementById('content').innerHTML = html;
}

async function homePage() {
    if (!state.token) {
        window.location.hash = '#/login';
        return;
    }
    render(`
        <div class="p-5 mb-4 bg-white rounded-3 shadow-sm">
            <h1 class="display-5 fw-bold">Welcome, ${state.user.email}</h1>
            <p class="col-md-8 fs-4">This is the new static frontend for SOMS Platform. Everything is served from an API.</p>
            <hr class="my-4">
            <div class="row g-4">
                <div class="col-md-4">
                    <div class="card h-100 border-0 shadow-sm">
                        <div class="card-body">
                            <h5 class="card-title">Learners</h5>
                            <p class="card-text">Manage your student records.</p>
                            <a href="#/learners" class="btn btn-outline-primary">View All</a>
                        </div>
                    </div>
                </div>
                <div class="col-md-4">
                    <div class="card h-100 border-0 shadow-sm">
                        <div class="card-body">
                            <h5 class="card-title">Assessments</h5>
                            <p class="card-text">Record marks and track progress.</p>
                            <a href="#/assessments" class="btn btn-outline-primary">Open Hub</a>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    `);
}

function loginPage() {
    render(`
        <div class="row justify-content-center">
            <div class="col-md-5">
                <div class="card shadow-lg border-0">
                    <div class="card-body p-5">
                        <h2 class="fw-bold text-center mb-4">Sign In</h2>
                        <form id="login-form">
                            <div class="mb-3">
                                <label class="form-label">Email</label>
                                <input type="email" id="email" class="form-control" value="admin@sowetohigh.edu.za" required>
                            </div>
                            <div class="mb-4">
                                <label class="form-label">Password</label>
                                <input type="password" id="password" class="form-control" value="password" required>
                            </div>
                            <button type="submit" class="btn btn-primary w-100">Login</button>
                        </form>
                    </div>
                </div>
            </div>
        </div>
    `);

    document.getElementById('login-form').addEventListener('submit', async (e) => {
        e.preventDefault();
        const email = document.getElementById('email').value;
        const password = document.getElementById('password').value;

        try {
            const data = await apiFetch('/auth/login', {
                method: 'POST',
                body: JSON.stringify({ email, password })
            });

            if (data.token) {
                localStorage.setItem('token', data.token);
                localStorage.setItem('user', JSON.stringify(data.user));
                state.token = data.token;
                state.user = data.user;
                updateNav();
                window.location.hash = '#/';
            }
        } catch (err) {
            alert('Login failed: ' + err.message);
        }
    });
}

async function learnersPage() {
    render('<div class="text-center"><div class="spinner-border text-primary"></div></div>');
    try {
        const learners = await apiFetch('/learners');
        let html = `
            <div class="d-flex justify-content-between align-items-center mb-4">
                <h2>Learners</h2>
                <button class="btn btn-primary">Add New</button>
            </div>
            <div class="table-responsive bg-white p-3 rounded shadow-sm">
                <table class="table table-hover">
                    <thead>
                        <tr>
                            <th>Full Name</th>
                            <th>Grade</th>
                            <th>Student ID</th>
                            <th>Actions</th>
                        </tr>
                    </thead>
                    <tbody>
        `;
        learners.forEach(l => {
            html += `
                <tr>
                    <td>${l.full_name}</td>
                    <td>${l.grade}</td>
                    <td>${l.student_id}</td>
                    <td><button class="btn btn-sm btn-outline-secondary">Edit</button></td>
                </tr>
            `;
        });
        html += '</tbody></table></div>';
        render(html);
    } catch (err) {
        render('<div class="alert alert-danger">Failed to load learners</div>');
    }
}

async function assessmentsPage() {
    render('<div class="text-center"><div class="spinner-border text-primary"></div></div>');
    try {
        const assessments = await apiFetch('/assessments');
        let html = `
            <div class="d-flex justify-content-between align-items-center mb-4">
                <h2>Assessments</h2>
                <button class="btn btn-primary">Create New</button>
            </div>
            <div class="row g-3">
        `;
        assessments.forEach(a => {
            html += `
                <div class="col-md-4">
                    <div class="card shadow-sm border-0">
                        <div class="card-body">
                            <h5 class="card-title">${a.title}</h5>
                            <h6 class="card-subtitle mb-2 text-muted">${a.subject} - ${a.type}</h6>
                            <button class="btn btn-sm btn-primary">Record Marks</button>
                        </div>
                    </div>
                </div>
            `;
        });
        html += '</div>';
        render(html);
    } catch (err) {
        render('<div class="alert alert-danger">Failed to load assessments</div>');
    }
}

init();